用脉冲光声法测量固体介质中声速

提出了一种利用脉冲光声技术测量固体介质中声速的方法,建立了由YAG激光器和超声探测器组成的实验系统,脉冲激光在固体表面产生脉冲超声波,通过测量脉冲声波在固体内多次反射后的出射信号及固体的厚度,即可算出固体介质中的声速.对黄铜及铝的测量结果表明,这是一种准确性较高的固体介质中声速测量方法.该测量方法可作为综合设计性物理实...     

用自相关法测量横向流速

以LabVIEW为平台,搭建了横向流速测量实验系统.流动微粒对探测光起阻挡作用,导致透射信号强弱变化,通过归一化自相关函数可以计算粒子通过探测区域的渡越时间,测量探测区域宽度后,可以计算得到流速.     

光学三维成像实验系统

建立光学投影层析三维成像系统,该系统包括光学成像、图像采集、断层重建及三维显示,重建算法为滤波反投影算法.实验结果表明:利用该系统得到的重建图像与样品的形状吻合,重建结果边缘清晰,伪迹较小.     

科研型实验教学模式的研究与实践

科学技术的高速发展对人的综合素质及创新能力的要求越来越高,而实验教学是本科生提高综合素质及培养创新能力不可缺少的平台．目前各高校都在积极进行实验教学的改革研究。从国内一些大学的实验教学改革来看,都有调整和增加综合性、设计性和研究性实验在实验教学中所占比例的趋势．     

Spectral domain optical coherence tomography with sub-micrometer sensitivity for measurement of central corneal thickness

We demonstrated a method for measurement of central corneal thickness(CCT) with a sub-micrometer sensitivity using a spectral domain optical coherence tomography system without needing a super broad bandwidth light source. By combining the frequency and phase components of Fourier transform, the method is capable of measurement of a large dynamic range with a high sensitivity. Absolute phases are retrieved by comparing the correlations between the detected and simulated interference fringes. The phase unwrapping ability of the present method was quantitatively tested by measuring the displacement of a piezo linear stage. The human CCTs of six volunteers were measured to verify its clinical application. It provides a potential tool for clinical diagnosis and research applications in ophthalmology.     

用电子散斑干涉法测微小角度

用电子散斑干涉法建立了微小角度定量测量系统,根据散斑噪声的特点,计算散斑图像沿不同方向的投影及投影的调制度,调制度最大值投影的周期为干涉条纹的宽度.实验结果表明该方法最小可测量角度为10-5 rad.     

基于1/4波片晶体电光调制输出特性的理论分析

根据铌酸锂晶体电光调制原理,推导了电光调制器透光率与1/4波片光轴方位的数学通式,通过数值计算分析了基于1/4波片晶体电光调制的输出特性.结果表明,波片每旋转π/4,周期性依次出现线性调制、非倍频失真和倍频失真,与实验结果相符.     

用阶跃法测量光声成像系统的点扩展函数

从理论上证明了光声成像系统的点扩展函数是边缘响应函数的一阶导数,提出了用阶跃法测量光声成像系统的点扩展函数,用染色琼脂对本方法进行了实验验证,理论计算结果和实验测量数据有很好的一致性,为复杂光声成像系统提供了一种简单实用的点扩展函数测量方法。     

Measurement of ocular axial length using full-range spectral-domain low-coherence interferometry

We demonstrate a system for measuring the ocular axial length(AL) with high sensitivity and high speed using spectral-domain low-coherence interferometry(SD-LCI). To address the limit in measuring such a large range by using SD-LCI, we propose a full-range method to recognize the positive and negative depths. The reference arm length is changed synchronously with the shift of the focal point of the probing beam. The system provides a composite depth range that is sufficient to cover the whole eye. We demonstrate the performance of the presented system by measuring the ALs of five volunteers. This system can provide the A-scan ocular biometric assessment of the corneal thickness and AL in 0.1 s.     

分光光度法测定食品中铁的含量

研究了显色剂4-(2-噻唑偶氮)间苯二酚(简称TAR)与铁(Ⅱ)的显色反应.实验表明,在pH=10.0的NH3-NH4Cl缓冲介质中,铁(Ⅱ)与TAR形成红色的络合物,其最大吸收波长位于733nm处,表观摩尔吸光系数为6.98×104L·mol-1·cm-1,铁(Ⅱ)含量在0-25μg/25mL范围内符合比耳定律.方法用于食品中微量铁的测定,结果令人满意.